Gluten cystein residue

Figure 6.1. The role of HMW subunits in gluten structure and functionality. Amino acid sequences derived from direct analysis of purified proteins and the isolation and sequencing of corresponding genes show that the proteins have highly conserved structures, with repetitive domains flanked by shorter nonrepetitive domains containing cysteine residues (SH) available for formation of interchain disulphide bonds. Molecular modelling indicates that the individual repetitive domains form a loose spiral structure (bottom right) while SPM shows that they interact by noncovalent forces to form fibrils (centre right). Includes figures from Parchment et al. (2001) and Humphries et al. (2000).

It has been possible to elucidate the position and type of the disulfide bonds so that the structure of the gluten proteins is discernible. First, a-glia-din, y-gliadin and the LMW subunits will be discussed based on two complementary schemes. Figure 15.10 shows the cysteine residues involved in infra- and intermolecular disulfide bridges. Figure 15.11 shows the extent of the relationship in the disulfide sfructures. 

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